Elastic filaments in skeletal muscle revealed by selective removal of thin filaments with plasma gelsolin.
Elastic filaments in skeletal muscle revealed by selective removal of thin filaments with plasma gelsolin.
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骨骼肌中的弹性细丝通过选择性去除血浆凝胶素的薄丝揭示。
DOI：
10.1083/jcb.110.1.53
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发表时间：
1990-01
期刊：
影响因子：
--
通讯作者：
Ishiwata S
中科院分区：
文献类型：
--
作者：
Funatsu T;Higuchi H;Ishiwata S
肌肉需要一个弹性框架来保持其机械稳定性。血浆明胶去除兔骨骼肌细丝揭示了弹力丝的本质特征。荧光显微镜下鬼臼乙素-罗丹明染色，电子显微镜下观察肌球蛋白亚段1形成的箭头，以及SDS-PAGE分析，证实了细丝的选择性去除。薄片电子显微镜显示连接粗丝和Z线的弹性细丝(直径约4 nm)。去除细丝后，僵硬和主动张力产生均丧失，但静息张力保持不变。这些观察结果表明，无细丝纤维维持着由粗丝、弹性丝和Z线串联而成的框架，这使骨骼肌的收缩系统具有被动弹性。温和的胰酶处理降低了残留在无细丝纤维中的静止张力。随着静息张力的降低和弹性细丝的消失，唯一被消化的蛋白质成分是α-连接蛋白(也称为titin 1)，它从α形式转化为β形式(分别从titin 1转化为2)。因此，我们得出结论，弹性细丝的主要蛋白质成分是α-连接素(Titin 1)。
Muscle needs an elastic framework to maintain its mechanical stability. Removal of thin filaments in rabbit skeletal muscle with plasma gelsolin has revealed the essential features of elastic filaments. The selective removal of thin filaments was confirmed by staining with phalloidin-rhodamine for fluorescence microscopy, examination of arrowhead formation with myosin subfragment 1 by electron microscopy, and analysis by SDS-PAGE. Thin section electron microscopy revealed the elastic fine filaments (approximately 4 nm in diameter) connecting thick filaments and the Z line. After removal of thin filaments, both rigor stiffness and active tension generation were lost, but the resting tension remained. These observations indicate that the thin filament-free fibers maintain a framework composed of the serial connections of thick filaments, the elastic filaments, and the Z line, which gives passive elasticity to the contractile system of skeletal muscle. The resting tension that remained in the thin filament-free fibers was decreased by mild trypsin treatment. The only protein component that was digested in parallel with the decrease in the resting tension and the disappearance of the elastic filaments was alpha-connectin (also called titin 1), which was transformed from the alpha to the beta form (from titin 1 to 2, respectively). Thus, we conclude that the main protein component of the elastic filaments is alpha-connectin (titin 1).